When monitoring the plasma/serum sodium concentration of sick newborn babies in neonatal intensive care units, it may be preferable to use direct ion-specific electrode (ISE) methodology incorporated in point-of-care analyzers (including blood gas analyzers), rather than the indirect ISE methodology commonly employed...

By measurement of partial pressure of oxygen (pO₂) and oxygen saturation (sO₂), arterial blood gas analysis provides the gold standard method for assessment of blood oxygenation and the means for monitoring supplemental oxygen therapy. More frequent use of arterial blood gases for this purpose will be required if the...

Hemolysis causes clinically significant bias in four of twelve parameters generated during blood gas analysis. That is the headline finding of a recently published study that is, according to the authors, the first ever to investigate the effect of hemolysis on blood gas analytes. Venous blood was sampled from nine...

Extracellular (serum) potassium concentration is normally maintained within the approximate reference range of 3.5-5.2 mmol/L; this is important for normal cardiac function. Both reduced serum potassium (hypokalemia) and increased serum potassium (hyperkalemia) can, if sufficiently severe, be associated with...

Arterial blood gas analysis in cases of metabolic acidosis reveals primary decrease in pH and bicarbonate, and secondary (compensatory) reduction in pCO₂. The most common cause of metabolic acidosis is increased production of endogenous metabolic acids, either lactic acid, in which case the condition is called lactic...

The incorporation of CO-oximeters in modern blood gas analyzers allows rapid determination of the amount of carboxyhemoglobin in blood. This, in turn, allows rapid diagnosis of carbon monoxide poisoning, the subject of a recently published review.  This wide-ranging review article begins with consideration of the...

The calcium present in blood plasma comprises two almost equal fractions: half is bound to albumin and the remainder is unbound, free ionized calcium. Only the free ionized calcium is physiologically active. There are two ways of assessing patient blood calcium status.  The first – at one time the only available...

Pulse oximeters, which are ubiquitous in nearly all areas of clinical care, provide the means for safe, non-invasive continuous monitoring of blood oxygen saturation. The validity of using pulse oximetry to assess patient blood oxygenation status depends on SpO₂, the parameter measured by pulse oximetry, being a...

Compared with other plasma electrolytes, such as sodium, potassium and bicarbonate, chloride usually gets very limited coverage in medical texts. Now in a wide-ranging review article chloride gets the exclusive billing that its physio-pathological significance deserves.  The article begins with consideration of the...

In health, plasma potassium concentration is maintained within the approximate range of 3.5-5.0 mmol/L. Hypokalemia, a very common electrolyte disturbance – present in up to 20 % of hospitalized patients – is diagnosed if plasma potassium is less than 3.5 mmol/L.  Although mild hypokalemia is often asymptomatic, a...